Electronic apparatus for determining identification metals and metal alloys



May 8, 1962 VANN YUEN 3,034,050

ELECTRONIC APPARATUS FOR DETERMINING IDENTIFICATION METALS AND METALALLOYS Filed Aug. 5, 1959 a 4 VACUUM TUBE Q VOLT METER I6 ,l4 l4' |2 -|&3

l8 SAMPLE; l7

JNVENTOR. VANN YUE ATTORNEYS Unite The invention described herein may bemanufactured and used by or for the United States Government forgovernmental purposes without payment to me of any royalty thereon.

This invention concerns an apparatus and a method for accomplishing thesegregation of unidentified and misidentified metal alloys withparticular reference to aluminum alloys such as those commonly used inaircraft and the like.

A background for the understanding of this invention is provided by thebook Metal Data by Samuel L. Hoyt published in 1952. by the ReinholdPublishing Corporation, New York 36, NY. at pages 369 et seq.; by thePatents 2,706,712, issued April 19, 1955 to Rolf K. Ladisch for aPortable Polarographic Half Cell; 2,366,844, issued January 9, 1945 toAntony Doschek for a Method Of And Means For Identifying Metals;2,531,747 issued Novem ber 28, 1950 to R. F. Steam for a MetalIdentifier; 2,553,- 068, issued May 15, 1951 to E. W. Tucker for anElectrolytic Cell; etc. A calomel electrode in RC1 is discussed brieflyat page 235 and elsewhere of Storage Batteries by George W. Vinalpublished in 1955 by John Wiley and Sons, Inc. New York City, NY.

A brief summary of the invention follows, indicating its nature andsubstance together with a statement of the objects of the inventioncommensurate and consistent with the invention as claimed and alsosetting out the exact nature, the operation and the essence of theinvention complete with proportions and techniques that are necessaryfor its use. The purpose of the invention also is stipulated. Thepresentation is adequate for any person who is skilled in the art andscience to which the invention pertains to use it without involvingextensive experimentation. The best mode of carrying out the inventionis presented by the citing of a specific operative example inclusive ofthe preparation and the use of at least one example of the invention.

This invention provides an apparatus and a process for applying themoist tip of a new and improved probe to a clean metal surface and froma voltage reading that is characteristic of the metal so contactedquickly and easily identify the metal without in any way damaging it.

states atent.

provement over the Beckman special types of electrodes, such as thecalomel electrode designated H-29330 in the 1955 Harshaw, ScientificCatalogue, published by the Harshaw Chemical Company, 1945 E. 97thStreet, Cleveland, Ohio. The Beckman electrode H-29330 is a doublejunction type wherein a permanently charged calomel-mercury column issealed into an intermediate tube filled with :1 KCl saturated solution.

The method proposed herein for the identification and the segregation ofaluminum alloys is not intended to replace chemical and spectrographicanalysis. Its application is rather the sorting and the identifying ofcommonly available alloys based on their electrical characteristics in arapid, easy and an economical manner without damage to the alloy soidentified.

In the accompanying drawing is shown a probe or an electrode assemblythat embodies the present invention. The electrode assembly comprises anupwardly open glass outside shell 1 that terminates downwardly in asmall apertured tip 2. An electrolyte is supplied to the outside shell 1through a lateral mouth 3 that is removably closed with a rubber cap 4.A plastic cap 5 closes the open upper ends of the outside shell 1 and ofan inside shell 6. The cap 5 supports at its center a platinum wire 7that extends axially down into the inside or innermost shell 6. Theinside shell 6 contains amixture of granular calomel 8 and potassiumchloride 9 dispersed through liquid mercury 10 around the platinum wire7.

The innermost shell 6 has its upper end secured in the plastic cap 5'-and its lower end apertured to open into the permeable lower part of anintermediate gas shield third shell 11. The gas shield, intermediate orthird shell 11 opens upwardly below the plastic cap 5 and within theglass outside first shell 1. The intermediate shell 11 is downwardlypermeable, as by the apertures 12 and 13, or the like, in ample numberto avoid a gas block in circuit. Fiber glass 14 and 14 serves to spacethe lower portions of the shells 1, 6 and 11 with respect to each other.

An output lead 15 has one of its ends connected to the positive terminalof a vacuum tube voltmeter 16 and its opposite end is secured by solderor the like to the upper end of the platinum wire 7. The negativeterminal of A probe that embodies a part of the present invention withits connections and an associated instrument, is shown in an elevationalaxial sectioned View in the single FIGURE of the accompanying drawing asan improved single electrode system or a half cell.

The probe is shown connected through leads to a vacuum tube voltmeterand in position formaking contact with a sample alloy. The probecontains a saturated calomel electrode with a liquid junction. Theimproved electrode embodies a gas shield to prevent a gas lock. This isa unique advantage when used with a hydrogen peroxide containingelectrolyte solution.

The calomel electrode that is disclosed herein is an imthe vacuum tubevoltmeter 16 is connected by the lead 17 to the alloy sample 18. Anillustrative vacuum tube voltmeter is shown in FIG. 15-1 on page 598 ofthe Theory and Applications of Electron Tubes by Herbert U. Reich,published in 1944 by the McGraw-Hill Book Company, New York city.

The electrolytic solution to be added through the lateral mouth 3 of theoutside shell :1 is prepared by mixing by volume four parts of-asaturated water solution of potassium chloride with one part of a 30%hydrogen peroxide solution and should be prepared immediately before itis used. The introduction of the electrolyte into the outside shell 1with'its tip 2 in contact with the sample 18 causes the electrolyte topass through the apertured tip 2 and to moisten the surface of thesample 18, or a drop of the electrolyte may be placed on the alloysample 18 at its point of contact with the tip 2' of the probe.

V The position of the needle on the scale of the voltmeter 16 indicatesa potential reading that is characteristic of many alloys, such as thoseused in the structure of aircraft and the like. Representative potentialmeter readare listed in the following chart:

Volt Al-Alloys 248 (clad with 23) eaken 1 MMHO sci-: m w

758 (clad with 728) appear at pages 369 and 370 of the Hoyt text.

In the above chart it will be noted that the aluminum alloys designated1 4s and 195 display on the vacuum tube voltmeter 16 a voltage of from0.60 to 0.63 volt as a potential that is characteristic of this group ofalloys. In other words, in the event the tip 2 of the electrode shown insection in the accompanying drawing in circuit is caused to contact analloy 14s or 195, the voltage reading on the vacuum tube voltmeter 16will be in the range of from 0.60 and 0.63 volt. The voltage reading0.63 is a potential characteristic of the aluminum alloy 24s.

In a similar way the voltage reading 0.71 indicates and is acharacteristic of the aluminum alloy 35 5. The alloy 61s has acharacteristic potential reading of 0.76. A voltage reading that fallswithin the range from 0.75 to 0.78 indicates the alloy 24s clad with thealloy 2s. The voltage reading 0.81 volt is characteristic of thealuminum alloy 3s. The alloys 2s and 356 both are characterizedby thevoltmeter reading- 0.83. The alloy 52s is indicated by the voltagereading 0.84 and the alloy 75s is indicated by the voltage reading 0.87.Readings on the voltmeter 16 between the range from 0.88 to 0.92 voltare character- 'istic of the aluminum alloy 75s clad with the alloy 72s.

The voltage reading 0.92 indicates the aluminum alloy 220 and thevoltage reading 094 indicates the alloy 72s. From the foregoingexperimental findings it will be apparent that, with the improvedhalfcell described and shown in; the accompanying drawings, other alloys,metals and the like will also display their;characteristic'voltages thatin a similar manner may be used to identify the embodies the presentinvention is to It is to be understood that the structural details ofthe probe that is disclosed herein and of the circuit in which it isused are illustrative of a successfully functioning apparatus and methodand that similarly functioning apparatus and method steps may besubstituted for those disclosed herein without departing from theinvention.

I claim:

l. A probe comprising an upwardly open glass outside shell thatterminates downwardly in a small apertured tip and that is provided witha mouth for the introduction of an electrolyte within the outside shell,a plastic cap closing the open upper end of the outside shell, aplatinum wire with its upper end exposed to outside the assembly byextending through and being secured to the plastic cap and the platinumwire extending axially within the glass outside shell, an inside shellwith its upper end closed by the plastic cap and terminating downwardlyin a small apertured tip, a mixture of granular'calomel and potassiurnchloride dispersed through liquid mercury within the inside shell, adownwardly permeable gas shield intermediate shell extending downwardlybelow the lower end of the inside shell and between the inside shell andthe outside shell, a first fiber glass means interposed between andmaintaining spacial relationship between the inside shell and the gasshield intermediate shell adjacent the lower ends'thereof, a secondfiber glass means interposed between and maintaining spacialrelationship between the gas shield intermediate shell and the outsideshell adjacent the lower ends thereof, and an electrolyte consisting ofa mixture by volume of four parts saturated water solution'of potassiumchloride and one part of 30% hydrogen peroxide solution within the lowerends of the insideshell and the gas shield intermediate shell and theoutside shell and the electrolyte being accessible to outsidethe probethrough the apertured tip at the lower end of the outside shell.

' 2. The probe in the above claim 1 wherein the upper end of the insideshell is secured in the plastic cap.

3. The process for segregating one unknown from an indeterminate groupof metals by its electrical characteristic by cleaning the surface ofthe unknown, contacting the cleaned surface of the unknown with anelectrolyte that consists of a mixture of by volume four parts of asaturated water solution of potassium chloride and one part of a 30%hydrogen peroxide solution, and contacting the electrolyte ofpotassiumchloride and hydrogen peroxide with a saturated mixture ofgranular calomel and potassium chloride as the dispersed phase throughliquid mercury as the dispersing medium, and determining as a physicalcharacteristic of the unknown the potential value of the electrolyterincontact with the unknown and in contact with the granular calomel andpotassium chloride in liquidmercury. 4. The process of determining the?electrical potential characteristic of an unknown mixture of metals asan alloy identifying physical constant thereof that is accomplishedbyelectrically contacting in a series connected potential indicatingelectrical circuit the unknown mixture of metals with an electrolyte ofthe composition by volume of four parts of a saturated water solution ofpotassium chloride and by volume one part of 30% hydrogen peroxidesolution, and connecting in series therewith a saturatedmixture ofgranular calomel and potassium chloride dispersed through liquid mercuryfor obtaining a potential reading that is characteristic of the unknownmixture of metals. Q

References Cited in the file of this patent UNITED STATES. PATENTS2,531,747 Stearn Nov. 28, 1950 2,665,412 Eding et al. Jan. 5, 19542,684,938 Mantzell July 27, 1954

3. THE PROCESS FOR SEGREGATING ONE UNKNOWN FROM AN INDETERMINATE GROUPOF METALS BY ITS ELECTRICAL CHARACTERISTIC BY CLEANING THE SURFACE OFTHE UNKNOWN CONTACTING THE CLEANED SURFACE OF THE UNKNOWN WITH ANELECTROLYTE THAT CONSISTS OF A MIXTURE OF BY VOLUME FOUR PARTS OF ASATURATED WATER SOLUTION OF POTASSIUM CHLORIDE AND ONE PART OF A 30%HYDROGEN PEROXIDE SOLUTION, AND CONTACTING THE ELECTROLYTE OF POTASSIUMCHLORIDE AND HYDROGEN PEROXIDE WITH A SATURATED MIXTURE OF GRANULARCALOMEL AND POTASSIUM CHLORIDE AS THE DISPERSED PHASE THROUGH LIQUIDMERCURY AS THE DISPERSING MEDIUM, AND DETERMINING AS A PHYSICALCHARACTERISTIC OF THE UNKNOWN THE POTENTIAL VALUE OF THE ELECTROLYTE INCONTACT WITH THE UNKNOWN AND IN CONTACT WITH THE GRANULAR CALOMEL ANDPOTASSIUM CHLORIDE IN LIQUID MERCURY.